Express your answer as a mixed number simplified to lowest terms. $12\dfrac{6}{8}-5\dfrac{3}{7} = {?}$
Solution: Separate the whole numbers from the fractional parts: $= {12} + {\dfrac{6}{8}} - {5} - {\dfrac{3}{7}}$ Bring the whole numbers together and the fractions together: $= {12} - {5} + {\dfrac{6}{8}} - {\dfrac{3}{7}}$ Subtract the whole numbers: $=7 + {\dfrac{6}{8}} - {\dfrac{3}{7}}$ Simplify each fraction: $= 7 + {\dfrac{3}{4}} - {\dfrac{3}{7}}$ Find a common denominator for the fractions: $= 7+\dfrac{21}{28}-\dfrac{12}{28}$ Subtract the fractions: $= 7+\dfrac{9}{28}$ Combine the whole and fractional parts into a mixed number: $= 7\dfrac{9}{28}$